Answered

Explore Westonci.ca, the premier Q&A site that helps you find precise answers to your questions, no matter the topic. Get immediate and reliable answers to your questions from a community of experienced experts on our platform. Get detailed and accurate answers to your questions from a dedicated community of experts on our Q&A platform.

Each year the US Environmental Protection Agency (EPA) releases fuel economy data on cars manufactured in that year. Below arc summary statistics on fuel efficiency (in miles/gallon) from random samples of cars with manual and automatic transmissions manufactured in 2012. Do these data provide strong evidence of a difference between the average fuel efficiency of cars with manual and automatic transmissions in terms of their average city mileage?

Sagot :

Answer:

Follows are the solution to this question:

Step-by-step explanation:

Please find the complete question in the attachment file.

[tex]n_1 = 26 \\\\ x_1 = 16.12 \\\\s_1 = 3.58\\\\n_2 = 26\\\\ x_2 = 19.85 \\\\ s_2 = 4.51[/tex]

[tex]H_0: u_1 = u_2\\\\H_1: u_1 \neq u_2[/tex]

Using formula:

[tex]\to S^{2}_{p}=\frac{S^{2}_{1}(n_1 -1)+ S^{2}_{2}(n_2-1)}{n_1+n_2-2}[/tex]

[tex]\to Sp^2 = \frac{((26-1) \times (3.58^2) + (26-1) \times (4.51^2))}{(26+26-2)}[/tex]

          [tex]= \frac{((25) \times 12.8164 + (25) \times 20.3401 )}{(26+24)}\\\\ = \frac{(320.41 + 508.5025)}{(50)}\\\\ = \frac{(828.9125)}{(50)}\\\\=16.57825[/tex]

[tex]\to Sp = 4.0716[/tex]

Calculating the value of standard error:

[tex]\to SE = Sp \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2}}[/tex]

          [tex]=4.0716 \times \sqrt{\frac{1}{26}+\frac{1}{26}}\\\\=4.0716 \times \sqrt{\frac{1+1}{26}}\\\\=4.0716 \times \sqrt{\frac{2}{26}}\\\\=4.0716 \times \sqrt{\frac{1}{13}}\\\\=4.0716 \times 0.277 \\\\=1.1278332\\\\= 1.1293[/tex]

Calculating the value of test statistic:

Formula:

[tex]\to t = \frac{(x_1-x_2)}{SE}[/tex]

      [tex]= \frac{(16.12 -19.85)}{1.1293}\\\\= \frac{(-3.73)}{1.1293}\\\\=-3.303[/tex]

Calculating the value of Degree of freedom:

[tex]= n_1+n_2 -2 \\\\= 26+26 -2 \\\\= 52 -2 \\\\= 50[/tex]

Because the P-value is a 2-tailed test = 0.0018

Thus they reject H0, because of P-value < 0.05,

Yeah, certain data show clearly that the means are different.

Thank you for visiting. Our goal is to provide the most accurate answers for all your informational needs. Come back soon. We hope our answers were useful. Return anytime for more information and answers to any other questions you have. We're here to help at Westonci.ca. Keep visiting for the best answers to your questions.